Process Evaluation: Using evaluation model of Reach, Effectiveness, Adoption, Implementation and Maintenance (RE-AIM) (Glasgow et al. 2001), a framework that emphasized on Reach, Effectiveness, Adoption, Implementation and Maintenance, the investigators will examine the extent to which the LHW program is carried out through processes as intended. At individual level, the investigators will focus on Reach (R) of the LHW certification program and hepatitis B free events and on the Efficacy/Effectiveness (E) of the LHW certification program. For the group level of aggregated individuals, the investigators will assess on Adoption (A), Implementation (I), and Maintenance (M). The investigators will assess general administrative processes of LHW program during the study period in the selected perspectives of fidelity (e.g. logistic reviews, completion rates), dose (e.g. satisfaction survey), and method on translated forms and tools (Saunders, Evans, & Joshi 2005).